Solid acid-base bifunctional catalyst for catalyzing acetonitrile and acrylonitrile to synthesize glutaronitrile and preparation method of solid acid-base bifunctional catalyst

Abstract

The invention relates to a solid acid-base bifunctional catalyst for catalyzing acetonitrile and acrylonitrile to synthesize glutaronitrile and a preparation method of the solid acid-base bifunctional catalyst, and belongs to the technical field of fine chemical synthesis. The catalyst breaks through the technical bottleneck that a homogeneous catalysis system is difficult to recycle, firstly, 1, 5, 7-triazabicyclo [4.4. 0] dec-5-ene (TBD) serves as a Lewis alkaline site in a bifunctional catalyst and is immobilized on cross-linked chloromethylated polystyrene resin to form PS-TBD, a Lewis acidic metal copper active center is introduced, and then the PS-TBD is immobilized on the cross-linked chloromethylated polystyrene resin to form PS-TBD; and a heterogeneous catalysis system with an acid-base synergistic catalysis function is constructed. In the specific implementation process, metal loading process parameters are optimized by the system, the spatial distribution of acidic sites (metal components) and alkaline sites (TBD) is ensured to achieve the optimal synergistic effect, and the finally obtained solid catalyst has certain catalytic activity and cycling stability and provides a certain material basis for industrial-grade continuous production of glutaronitrile.

Description

Technical Field

[0001] This invention belongs to the field of fine chemical synthesis technology and specifically relates to a solid acid-base bifunctional catalyst for catalyzing the synthesis of glutaronitrile from acetonitrile and acrylonitrile. The catalyst is suitable for the industrial production of glutaronitrile. This bifunctional solid acid-base catalyst possesses both acidic sites (metal components) and basic sites (TBDs), exhibits high catalytic activity and cyclic stability, and provides a material foundation for the industrial-scale continuous production of glutaronitrile. Background Art

[0002] The cyano group is one of the most important functional groups in chemistry and holds significant importance in today's chemical industry. Glutaronitrile, a representative of dinitrile compounds, also holds significant industrial value, being widely used in polymer materials, pharmaceutical intermediates, and fine chemicals, playing a crucial role in materials science and organic synthesis. However, its industrial production is still limited by the high cost and harsh conditions of traditional synthesis methods, necessitating independent innovation.

[0003] Although glutaronitrile has received relatively little attention, its synthesis methods have also attracted much attention as a dinitrile monomer precursor for high-end polymer materials such as polyamide engineering plastics and high-grade polyurethanes. For example, reported methods include a scheme for converting aldehydes into nitriles in one step using ammonium bromide and iodine in aqueous ammonia and a method for converting aldehydes into nitriles using hydroxylamine-O-sulfonic acid in an acidic solution ((a) Wang J, Yang XQ, Li N, et al. ChemistrySelect. 2022, 7, 1-4. (b) Quinn DJ, HaunG J, Moura-Letts G. Tetrahedron Lett .2016, 57 , 3844-3847.); A method for the direct synthesis of nitriles from terminal alkynes catalyzed by silver-bismuth hybrid materials (Ötvös SB, Mészáros R, Varga G, et al. Green Chem. 2018, 20, 1007-1019.); A method for synthesizing nitrile compounds by electrooxidative coupling of primary alcohols and ammonia over palladium nanoparticle-modified copper oxide nanowire catalysts (Fang Z, Ding Y, Wang M, et al. Appl. Catal., B. 2023, 337, 1-10); a method for converting primary amides or aldoximes into nitrile compounds using diethylaminodifluorosulfenammonium tetrafluoroborate (Paquin JF, Keita M, Vandamme M. Synthesis, 2015, 47, 3758-3766); and a method for synthesizing glutaronitrile from acetonitrile and acrylonitrile using carbon dioxide (Zhang Wenzhen. A Carbon Dioxide-Promoted Method for the Synthesis of Glutaronitrile and Other Condensation Monomer Precursors from Acetonitrile: China, CN202210671225.4[P]. 2023,03,03). Currently, there is no large-scale industrial synthesis method for glutaronitrile. This is primarily due to several drawbacks to current methods, such as the expensive and difficult-to-obtain catalysts required, high energy consumption, difficulty in obtaining substrates, and the inability to recycle the catalysts. Summary of the Invention

[0004] To solve the above-mentioned problems in the production of glutaronitrile, the present invention provides a method for economically, efficiently and greenly synthesizing glutaronitrile using inexpensive and readily available acetonitrile and acrylonitrile as raw materials and catalyzed by a solid acid-base bifunctional catalyst.

[0005] Solid catalysts typically consist of an active component, a support, and a co-catalyst. The active component is the primary catalytic agent, such as a metal or metal oxide; the support provides structural support and increases surface area, such as alumina or silica; and the co-catalyst enhances activity or stability. Solid acid-base synergistic catalysts are a class of solid materials with both acidic and basic sites. These two types of active sites synergistically enhance reaction efficiency and selectivity in catalytic reactions. Supported acid-base bifunctional synergistic catalysts, as novel heterogeneous catalytic materials, are innovative in that they achieve a molecular-level synergistic catalytic effect through the precise construction of two active sites (acidic and basic). This spatially adjacent bifunctional structure not only significantly enhances catalytic activity through electronic synergy between the acidic and basic sites but also optimizes reaction path selectivity through transition state stabilization. Compared to traditional homogeneous acid-base catalytic systems, these solid catalysts maintain high catalytic performance while offering excellent recyclability, environmental compatibility, and operational stability, providing an ideal platform technology for the development of green chemical processes.

[0006] This research focuses on developing a green synthesis process for glutaronitrile with industrial potential. The key breakthrough lies in the innovative design and preparation of a supported acid-base bifunctional synergistic catalytic material. By regulating the synergistic interaction between Lewis acidic sites (which activate substrate molecules) and Lewis basic sites (which promote nucleophilic addition reactions), this catalyst achieves multi-cycle stability while maintaining high catalytic performance. This property is crucial for industrial continuous production. This research not only provides a new catalytic solution for the cyanomethylation reaction but also lays a key technical foundation for the green, large-scale production of glutaronitrile.

[0007] Guided by the above design principles, this invention overcomes the technical bottleneck of homogeneous catalytic systems that are difficult to recycle. First, 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) is immobilized on a cross-linked chloromethylated polystyrene resin to form PS-TBD, acting as the Lewis basic site in a bifunctional catalyst. Lewis-acidic copper metal active centers are then introduced to construct a heterogeneous catalytic system with acid-base synergistic catalysis. During implementation, the metal loading process parameters were systematically optimized to ensure the optimal spatial distribution of the acidic sites (metal component) and basic sites (TBD) for a synergistic effect. The resulting solid catalyst exhibits both high catalytic activity and cyclic stability, providing a material foundation for the industrial-scale continuous production of glutaronitrile.

[0008] The technical solution of the present invention: A method for preparing a solid acid-base bifunctional catalyst for catalyzing the synthesis of glutaronitrile from acetonitrile and acrylonitrile comprises: loading 1,5,7-triazabicyclo[4.4.0]dec-5-ene on a chloromethylated polystyrene resin and then loading copper ions to prepare PS-TBD-Cu(I) or PS-TBD-Cu(II).

[0009] Furthermore, the method specifically comprises the following steps: (1) Chloromethylated polystyrene resin reacts with 1,5,7-triazabicyclo[4.4.0]dec-5-ene to obtain PS-TBD; (2) PS-TBD reacts with a copper salt, and after the reaction is completed, a solid sample is filtered, washed, and dried to obtain PS-TBD-Cu(I) or PS-TBD-Cu(II); the copper salt is a monovalent copper salt or a divalent copper salt.

[0010] Furthermore, the mass ratio of the reaction of 1,5,7-triazabicyclo[4.4.0]dec-5-ene and chloromethylated polystyrene resin is 1: (1~50).

[0011] Furthermore, the mass ratio of the copper salt to PS-TBD is 1: (1~50).

[0012] Furthermore, the monovalent copper salt is cuprous iodide, cuprous bromide, cuprous chloride, cuprous thiophene-2-carboxylate, cuprous cyanide, cuprous acetate, or tetraacetic copper hexafluorophosphate.

[0013] Furthermore, the divalent copper salt is copper acetate, copper sulfate, copper nitrate, copper oxalate, or copper stearate.

[0014] Furthermore, the reaction conditions of the PS-TBD and copper salt are stirring at 0-60° C. for 6-48 hours.

[0015] A solid acid-base bifunctional catalyst for catalyzing the synthesis of glutaronitrile from acetonitrile and acrylonitrile is prepared by adopting the above preparation method.

[0016] Furthermore, in the catalyst, 1,5,7-triazabicyclo[4.4.0]dec-5-ene serves as a Lewis basic site, and monovalent copper or divalent copper serves as a Lewis acidic site.

[0017] The catalyst is used for catalyzing the reaction of acetonitrile and acrylonitrile to synthesize glutaronitrile.

[0018] Beneficial effects of the present invention: The present invention proposes a method for preparing a type of solid acid-base bifunctional catalyst, which utilizes this type of solid acid-base bifunctional catalyst to achieve economical, efficient and green synthesis of glutaronitrile. A scheme for constructing a chloromethylated polystyrene resin-supported bifunctional catalyst was designed: first, TBD was immobilized on a cross-linked chloromethylated polystyrene resin to form PS-TBD, thereby achieving heterogeneous transformation of the catalyst; then, Lewis acidic metal active centers were introduced to construct a heterogeneous catalytic system with acid-base synergistic catalytic functions. During the specific implementation process, the metal loading process parameters were systematically optimized to ensure that the spatial distribution of acidic sites (metal components) and basic sites (TBD) achieved the optimal synergistic effect. The solid catalyst finally obtained has both certain catalytic activity and cyclic stability, providing a certain material basis for the industrial-grade continuous production of glutaronitrile. DETAILED DESCRIPTION

[0019] Specifically, a solid acid-base bifunctional catalyst for catalyzing the synthesis of glutaronitrile from acetonitrile and acrylonitrile requires the synthesis of solid acid-base bifunctional catalysts PS-TBD-Cu(I) and PS-TBD-Cu(II). Before synthesizing the solid acid-base bifunctional catalyst, PS-TBD must first be synthesized.

[0020] Synthesis of PS-TBD: Add 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) and chloromethylated polystyrene resin to a reactor and stir at 60-120°C for 24-72 hours. After the reaction, filter the solid sample, wash it three times with dichloromethane and three times with ethyl acetate, and dry it to constant weight. PS-TBD was then used to synthesize the solid acid-base bifunctional catalysts PS-TBD-Cu(I) and PS-TBD-Cu(II).

[0021] Synthesis of PS-TBD-Cu(I): Add PS-TBD and monovalent copper salt to a reactor and stir at 0-60°C for 6-48 hours. After the reaction, filter the solid sample, wash it three times with acetonitrile, tetrahydrofuran, and dichloromethane, and dry it to constant weight.

[0022] Synthesis of PS-TBD-Cu(II): Add PS-TBD and divalent copper salt to a reactor and stir at 0-60°C for 6-48 hours. After the reaction, filter the solid sample, wash it three times with methanol, dichloromethane, and diethyl ether, and dry it to constant weight.

[0023] The above reaction is shown in the following formula:

[0024] The mass ratio of TBD to chloromethylated polystyrene resin added to PS-TBD is 1: (1~50).

[0025] The added monovalent copper substrates are cuprous iodide, cuprous bromide, cuprous chloride, cuprous thiophene-2-carboxylate, cuprous cyanide, cuprous acetate, and tetraethylcyanocopper hexafluorophosphate.

[0026] The added divalent copper substrates are copper acetate, copper sulfate, copper nitrate, copper oxalate and copper stearate.

[0027] The mass ratio of the monovalent copper substrate described in PS-TBD-Cu(I) to PS-TBD is 1: (1~50).

[0028] The mass ratio of divalent copper substrate to PS-TBD in PS-TBD-Cu(II) is 1: (1~50).

[0029] After synthesizing the solid acid-base bifunctional catalyst, the present invention adds the solid acid-base bifunctional catalyst to a reaction flask, a reactor, or a fixed-bed reactor, adds acetonitrile and acrylonitrile as raw materials, adds a solvent, and then introduces carbon dioxide. The mixture is stirred and reacted at 40 to 100 degrees Celsius for 6 to 24 hours. After the reaction is completed, the mixture is cooled to room temperature and the gas is slowly released. The resulting reaction solution is fractionated by column chromatography to obtain a glutaronitrile product. The unreacted acrylonitrile and acetonitrile are recovered and can be reacted again.

[0030] The specific implementation of the present invention is further described below in conjunction with the technical solution. Example 1

[0031] Place a clean 100 mL three-necked flask, matching ground-mouth stopper, and magnetic stirrer in an oven and dry for 1 hour. After taking it out, apply vaseline evenly on the ground-mouth joint while it is still hot and assemble it. Then connect a double-row tube to evacuate the flask while it is still hot. After it is evacuated to room temperature, perform three argon replacement operations using the double-row tube. Under the protection of argon atmosphere, inject TBD (0.83 g, 6 mmol), chloromethylated polystyrene resin (2 g, 1.0-1.24 mmol / g), and toluene (20 mL) into the system through the sample funnel. After the drug is added, plug it with a ground-mouth stopper and place it in an oil bath to heat. In an argon atmosphere, heat it at 100 o After the reaction was completed, the three-necked flask was removed from the oil bath and cooled to room temperature. The filter cake was then washed three times with dichloromethane and ethyl acetate, respectively, and placed in a vacuum drying oven at 60 o C for 6 hours to obtain PS-TBD (2.166 g, 76.5%) as a pale yellow solid. Example 2

[0032] Place a clean 100 mL three-necked flask, matching ground-mouth stopper, and magnetic stirrer in an oven to dry for 1 hour. After taking it out, apply vaseline evenly on the ground-mouth joint while it is still hot and assemble it. Then, connect a double-row tube to evacuate the flask while it is still hot. After it is evacuated to room temperature, use the double-row tube to perform argon replacement operations three times. Under the protection of argon atmosphere, add copper iodide (0.378 mmol, 72 mg), PS-TBD (1.0 g, 1.0 mmol / g), and acetonitrile (35 mL) into the system through a sample funnel and react at room temperature under argon atmosphere for 24 hours. After the reaction is completed, filter the solid sample, wash it three times with acetonitrile, tetrahydrofuran, and dichloromethane, and place it in a vacuum drying oven at 60 o C for 6 hours to constant weight, and finally Cu + Solid acid-base bifunctional catalyst PS-TBD-Cu(I) supported on PS-TBD (green solid, 1.02 g, 2.0 wt% copper content). Example 3

[0033] Place a clean 100 mL three-necked flask, matching ground-mouth stopper, and magnetic stirrer in an oven to dry for 1 hour. After taking it out, apply vaseline evenly to the ground-mouth joint while it is still hot and assemble it. Then, connect a double-row tube to evacuate the flask while it is still hot. After evacuating to room temperature, use the double-row tube to perform argon replacement operations three times. Under the protection of argon atmosphere, add cuprous acetate (0.189 mmol, 36 mg), PS-TBD (1.0 g, 1.0 mmol / g), and acetonitrile (35 mL) into the system through a sample funnel and react at room temperature under argon atmosphere for 24 hours. After the reaction is completed, filter the solid sample, wash it three times with acetonitrile, tetrahydrofuran, and dichloromethane, and place it in a vacuum drying oven at 60 o C for 6 hours to constant weight, and finally Cu + Solid acid-base bifunctional catalyst PS-TBD-Cu(I) supported on PS-TBD (green solid, 1.01 g, 1.2 wt% copper content). Example 4

[0034] Place a clean 100 mL three-necked flask, matching ground-mouth stopper, and magnetic stirrer in an oven to dry for 1 hour. After taking it out, apply vaseline evenly on the ground-mouth joint while it is still hot and assemble it. Then, connect a double-row tube to evacuate the flask while it is still hot. After evacuating to room temperature, use the double-row tube to perform argon replacement operations three times. Under the protection of argon atmosphere, add cuprous acetate (0.095 mmol, 18 mg), PS-TBD (1.0 g, 1.0 mmol / g), and acetonitrile (35 mL) into the system through a sample funnel and react at room temperature under argon atmosphere for 24 hours. After the reaction is completed, filter the solid sample, wash it three times with acetonitrile, tetrahydrofuran, and dichloromethane, and place it in a vacuum drying oven at 60 o C for 6 hours to constant weight, and finally Cu + Solid acid-base bifunctional catalyst PS-TBD-Cu(I) supported on PS-TBD (green solid, 1.01 g, 0.7 wt% copper content). Example 5

[0035] Place a clean 100 mL three-necked flask, matching ground-mouth stopper, and magnetic stirrer in an oven to dry for 1 hour. After taking it out, apply vaseline evenly on the ground-mouth joint while it is still hot and assemble it. Then, connect a double-row tube to evacuate the flask while it is still hot. After it is evacuated to room temperature, use the double-row tube to perform argon replacement operations three times. Under the protection of argon atmosphere, copper acetate (0.330 mmol, 60 mg), PS-TBD (1.0 g, 1.0 mmol / g), and tetrahydrofuran solution (20 mL) are added to the system through a sample funnel and reacted at room temperature under argon atmosphere for 24 hours. After the reaction is completed, the solid sample is filtered, washed three times with methanol, dichloromethane, and ether, and placed in a vacuum drying oven at 60 o C for 6 hours to constant weight, and finally Cu 2+ Solid acid-base bifunctional catalyst PS-TBD-Cu(II) supported on PS-TBD (green solid, 1.02 g, 1.8 wt% copper content). Example 6

[0036] Place a clean 100 mL three-necked flask, matching ground-mouth stopper, and magnetic stirrer in an oven to dry for 1 hour. After taking it out, apply vaseline evenly on the ground-mouth joint while it is still hot and assemble it. Then, connect a double-row tube to evacuate the flask while it is still hot. After it is evacuated to room temperature, use the double-row tube to perform argon replacement operations three times. Under the protection of argon atmosphere, copper acetate (0.165 mmol, 30 mg), PS-TBD (1.0 g, 1.0 mmol / g), and tetrahydrofuran solution (20 mL) are added to the system through a sample funnel and reacted at room temperature under argon atmosphere for 24 hours. After the reaction is completed, the solid sample is filtered, washed three times with methanol, dichloromethane, and ether respectively, and placed in a vacuum drying oven at 60 o C for 6 hours to constant weight, and finally Cu 2+ Solid acid-base bifunctional catalyst PS-TBD-Cu(II) supported on PS-TBD (green solid, 1.01 g, 1.0 wt% copper content). Example 7

[0037] Place a clean 100 mL three-necked flask, matching ground-mouth stopper, and magnetic stirrer in an oven to dry for 1 hour. After taking it out, apply vaseline evenly on the ground-mouth joint while it is still hot and assemble it. Then, connect a double-row tube to evacuate the flask while it is still hot. After it is evacuated to room temperature, use the double-row tube to perform argon replacement operations three times. Under the protection of argon atmosphere, copper acetate (0.083 mmol, 15 mg), PS-TBD (1.0 g, 1.0 mmol / g), and tetrahydrofuran solution (20 mL) are added to the system through a sample funnel and reacted at room temperature under argon atmosphere for 24 hours. After the reaction is completed, the solid sample is filtered, washed three times with methanol, dichloromethane, and ether respectively, and placed in a vacuum drying oven at 60 o C for 6 hours to constant weight, and finally Cu 2+ Solid acid-base bifunctional catalyst PS-TBD-Cu(II) supported on PS-TBD (green solid, 1.01 g, 0.6 wt% copper content). Example 8

[0038] A 20 mL autoclave was charged with a stirrer, 0.4 mmol of acrylonitrile, 200 mg of PS-TBD-Cu(I) (2.0 wt% copper content), and 2.0 mL of acetonitrile. 2.0 MPa of carbon dioxide was introduced and stirred at 80°C for 12 hours. The carbon dioxide was then slowly released. The reaction mixture was then rotary evaporated to remove the acetonitrile, yielding a crude product. The desired product was then purified by column chromatography using a 1:1 volume ratio of ethyl acetate to petroleum ether as the eluent. The yield was 26%. Example 9

[0039] A 20 mL autoclave was charged with a stirrer, 0.4 mmol of acrylonitrile, 200 mg of PS-TBD-Cu(II) (1.8 wt% copper content), and 2.0 mL of acetonitrile. Carbon dioxide (2.0 MPa) was introduced and stirred at 80°C for 12 hours. The carbon dioxide was then slowly released. The acetonitrile was removed by rotary evaporation under reduced pressure to obtain a crude product. The desired product was then purified by column chromatography using a 1:1 volume ratio of ethyl acetate to petroleum ether as the eluent. The yield was 31%.

[0040] The above embodiments are only used to illustrate the present invention. Any equivalent transformations and improvements based on the technical solution of the present invention should not be excluded from the protection scope of the present invention.

Claims

1. A method for preparing a solid acid-base bifunctional catalyst for catalyzing the synthesis of glutaronitrile from acetonitrile and acrylonitrile, characterized in that: The method comprises the following steps: loading 1,5,7-triazabicyclo[4.4.0]dec-5-ene on a chloromethylated polystyrene resin and then loading copper ions to prepare PS-TBD-Cu(I) or PS-TBD-Cu(II).

2. The method according to claim 1, characterized in that The method specifically comprises the following steps: (1) Chloromethylated polystyrene resin reacts with 1,5,7-triazabicyclo[4.4.0]dec-5-ene to obtain PS-TBD; (2) PS-TBD reacts with a copper salt, and after the reaction is completed, a solid sample is filtered, washed, and dried to obtain PS-TBD-Cu(I) or PS-TBD-Cu(II); the copper salt is a monovalent copper salt or a divalent copper salt.

3. The method according to claim 2, wherein The mass ratio of the reaction of 1,5,7-triazabicyclo[4.4.0]dec-5-ene and chloromethylated polystyrene resin is 1: (1-50).

4. The method according to claim 2, characterized in that The mass ratio of the copper salt to PS-TBD is 1: (1-50).

5. The method according to claim 2, characterized in that The monovalent copper salt is cuprous iodide, cuprous bromide, cuprous chloride, cuprous thiophene-2-carboxylate, cuprous cyanide, cuprous acetate, and tetraethylcyanocopper hexafluorophosphate.

6. The method according to claim 2, characterized in that The divalent copper salt is copper acetate, copper sulfate, copper nitrate, copper oxalate, and copper stearate.

7. The method according to claim 2, characterized in that The PS-TBD and copper salt are reacted at 0-60° C. under stirring for 6-48 hours.

8. A solid acid-base bifunctional catalyst for catalyzing the synthesis of glutaronitrile from acetonitrile and acrylonitrile, characterized in that: The catalyst is prepared by the preparation method according to any one of claims 1 to 7.

9. The catalyst according to claim 8, characterized in that: In the catalyst, 1,5,7-triazabicyclo[4.4.0]dec-5-ene serves as a Lewis basic site, and monovalent copper or divalent copper serves as a Lewis acidic site.

10. Use of the catalyst according to claim 8, characterized in that: The catalyst is used for catalyzing the reaction of synthesizing glutaronitrile from acetonitrile and acrylonitrile.

Images